1. Field of the Invention
The present invention generally relates to load and/or unload operation control methods (hereinafter simply referred to as load/unload operation control methods) and storage apparatuses, and more particularly to a load/unload operation control method which controls a load operation which loads a recording and/or reproducing means such as a magnetic head with respect to a recording medium and/or controls an unload operation which unloads the recording and/or reproducing means from the recording medium, and to a storage apparatus which employs such a load/unload operation control method.
In a magnetic disk unit, a magnetic head is provided on a tip end of an arm, and a recording and/or reproducing (hereinafter simply referred to as recording/reproducing) of information with respect to a desired position on a magnetic disk is carried out by moving the arm. In a state where no information recording/reproducing is carried out, the magnetic head is unloaded from a position above the recording surface of the magnetic disk to a parking area, so that the magnetic head will not hit the magnetic disk when an external disturbance such as shock and vibration is applied on the magnetic disk unit. By unloading the magnetic head to the parking area, it is possible to prevent damage to the magnetic head and/or the magnetic disk due to the collision therebetween. When resuming the information recording/reproducing, the magnetic head at the parking area is loaded to a desired position above the recording surface of the magnetic disk.
2. Description of the Related Art
In order to prevent collision of the magnetic head and the magnetic disk during the load/unload operation, the arm is designed to move on a ramp member. More particularly, during the unload operation, the arm moves from a state where the magnetic head is positioned above the recording surface of the magnetic disk, moves up on a first sloping part of the ramp member, moves on a horizontal part of the ramp member, moves down on a second sloping part of the ramp member, and finally reaches the parking area. During the load operation, the arm moves in a sequence in reverse to that during the unload operation. For example, the arm is moved by a driving means such as a voice coil motor (VCM).
In addition, in order to prevent the magnetic head in the parking area from moving above the recording surface of the magnetic disk due to external shock or vibration, the arm in the parking area is held by a mechanical catch such as a magnetic catch in a state where the magnetic head is located in the parking area, so as to hold the magnetic head in the parking area.
Conventionally, in order to positively separate the arm in the parking area from the magnetic catch when carrying out the load operation, a current supplied to the VCM is sharply increased. In addition, in order to make the arm positively ride over the sloping part of the ramp member during the load operation, the current supplied to the VCM is sharply increased. Furthermore, during the unload operation, the current supplied to the VCM is sharply decreased when the arm reaches the parking area.
However, there was a problem in that mechanical noise is generated in the conventional magnetic disk unit because of the need to sharply change the current supplied to the VCM.
The mechanical noise is particularly unpleasant to the user in information processing apparatuses in which the load/unload operation is frequently carried out. Such information processing apparatuses include portable information processing apparatuses which use a battery as a power source, wherein a power save mode is provided to reduce unnecessary power consumption and the load/unload operation is frequently carried out in order to prevent collision of the magnetic head and the magnetic disk.
Of course, the above described problems are not peculiar to magnetic disk units, and similar problems were generated in storage apparatuses provided with the so-called ramp load/unload mechanism.